When a building is built or renovated, and in particular a building for professional use, it is advantageous to provide it with precabled networks (low voltage power supply network for powering electrical apparatus, lighting, etc.; very low voltage networks for telephone and computer links) which precabled networks should be simultaneously "systematic", "unspecialized", and "reconfigurable". A precabled network is said to be "systematic" when each work station within a building or a zone of a building that has been divided up into a plurality of potential work stations is provided with a suitable number of possible connections. A precabled network is said to be "unspecialized" when all of the cables it uses are identical and suitable for establishing any type of link. Finally, a precabled network is said to be "reconfigurable" when the connections and links that it makes possible can be modified at will without altering the actual structure of the network. Precabling systems for making networks of this type have numerous advantages over conventional cabling performed on a "blow-by-blow" basis as needs arise:
buildings can be adapted instantly to changes in the human organizations they contain;
there is no need for highly qualified personnel either to install them in the first place or to make proper use of them subsequently;
they are reliable, with the use of identical cables making it easier to check out a system thoroughly using a single test apparatus, and faulty items can be replaced by being interchanged with working items; and
they are cheap since the extra cost incurred of installation compared with conventional cabling is minimal and is rapidly compensated by the low cost that such cabling requires for extensions and adaptations to meet new requirements.
A systematic, unspecialized, and reconfigurable cabling system for a very low voltage telephone and/or computer network in a building is described in published French patent number 2 609 218. According to this publication, in a building which is subdivided into a plurality of work stations, each work station is connected by at least one precabling element to a subsidiary distribution premises. The subsidiary distribution premises contains at least two subsidiary distribution frames (one being for telephone links and the other for computer links), thereby enabling any work station to be connected to any other work station. A subsidiary distribution frame comprises an assembly of connection modules each containing a plurality of pairs of contacts. All of the precabling elements are identical and are constituted by a cable comprising a plurality of pairs of wires connected at one of its ends to a module disposed in the subsidiary distribution premises where the wires are connected to the modules of the two different subsidiary distribution frames. The other end of the precabling element is connected to a contact strip, which strip includes at least as many contacts as the cable has wires.
The end of the precabling element which is connected to the contact strip is disposed in a work station where it is suitable for being connected via the contacts of said strip to electrical terminations (e.g. sockets for computer purposes or telephone purposes, etc.). According to said prior patent publication. a building may be subdivided into a plurality of zones each served by a corresponding subsidiary distribution premises. In this case, the subsidiary distribution frames of the various zones are interconnected by cables referred to as "trunks".
The cabling system whose characteristics have been briefly outlined above is thus suitable for providing a building with a very low voltage network which is systematic, unspecialized, and reconfigurable. Unfortunately, it is not exactly suited to present requirements since it is only capable of equipping work stations in part since they also require a low voltage (i.e. mains) power supply. Further, considerable manpower is required to install the system since the precabling elements used must be adjusted in length and connected at both ends, firstly to electrical terminations (e.g. sockets for computers and telephones) and secondly to the connection modules of a subsidiary distribution frame. Making connections to a distribution frame of any kind is not particularly simple, and the above-mentioned patent specification specifies that each subsidiary distribution premises contains two distribution frames, one for telephone purposes and the other for computer purposes.
The object of the present invention is to improve prior art cabling systems of the type mentioned above. The present invention seeks to provide a precabling system for the low voltage network and for the very low voltage network of a building, said system including, in particular, precabling elements which can be completely manufactured in a factory, ready for use.
The invention provides for a cabling system both for the very low voltage telephone and computer network and for the low voltage power supply network of a building subdivided into work stations in which each work station is provided with at least one low voltage power supply outlet connected to a low voltage power supply bus, at least one telephone socket, and at least one computer socket, with it being possible to establish a telephone link between any two work stations via a subsidiary distribution frame, a main telephone distribution frame, and an automatic exchange, with it being possible to establish a computer link between any two work stations and/or between any work station and a central service (e.g. a mainframe computer) via at least one subsidiary distribution frame, with the same subsidiary distribution frame being used for establishing both telephone links and computer links between any two work stations.